Odontosyllis aracaensis, Fukuda, Marcelo Veronesi, Nogueira, João Miguel De Matos, Paresque, Karla & Martín, Guillermo San, 2013

Fukuda, Marcelo Veronesi, Nogueira, João Miguel De Matos, Paresque, Karla & Martín, Guillermo San, 2013, Species of Odontosyllis Claparède, 1863 (Annelida: Polychaeta: Syllidae) occurring along the Brazilian coast, Zootaxa 3609 (2), pp. 142-162 : 144-154

Odontosyllis aracaensis sp. nov.

Figures 1 A; 2–3; Table 1

Material examined. Project ‘BioPol-SP’. São Sebastião—Praia do Araçá (23°48’54”S 45°24’24”W): 7 specs (MZUSP 1017, holotype; ZUEC-POL 11891, paratype 1; MNCN 16.01/14458, paratype 4; MZUSP 1018, paratype 5; MZUSP 1175, one paratype), 20 Jul 2005; Praia da Baleia (23°48’54”S 45°39’51”W): 2 specs, 23 Jul 2005. Guarujá—Praia de Pernambuco (23°58’20”S 46°11’02”W): 1 spec. (MZUSP 1247), 22 Jun 2006. São Vicente—Ilha Porchat (23°58’39”S 46°22’08”W): 6 specs (MNCN 16.01/14457, paratype 2; ZUEC-POL 11892, paratype 3; MZUSP 1019, four paratypes), 18 Apr 2008.

Project ‘BioPol-NE’. Mataraca—Barra de Camaratuba (6°36’12’’S 34°57’52’’W): 1 spec. (MZUSP 1227), 12 Aug 2010. Baía da Traição—Praia do Farol (6°41’20’’S 34°55’48’’W): 16 specs (MZUSP 1228), 9 Aug 2010. Rio Tinto—Barra de Mamanguape (6°46’9’’S 34°55’2’’W): 8 spec. (MZUSP 1229), 11 Aug 2010. Conde—Praia de Jacumã (7°16’40’’S 34°47’54’’W): 1 spec. (MZUSP 1230), 20 Jan 2010; Praia de Coqueirinho (7°19’57’’S 34°47’41’’W): 1 spec. (MZUSP 1231), 28 Aug 2011.

Type series. Data of selected specimens of the type series are provided in Table 1.

Additional material examined. Odontosyllis fulgurans (Audouin & Milne Edwards, 1833) . North Sea (59°05'N 2°21'W, 76 m): 3 specs (ZMH-P13322), coll. Institute für Meeresforschung Bremerhaven, det. G. Hartmann-Schröder, 1972. Odontosyllis fulgurans dolerens Westheide, 1974 . Pacific Ocean, Galápagos, Santa Cruz: 1 spec. (holotype, ZMH P-13609), coll. & det. W. Westheide, 1972.

Description. Medium-sized body, holotype largest specimen analysed, 13 mm long, 0.69 mm wide, with 84 segments (Table 1). Conspicuous pigmentation on living animals, dorsally with dark line on anterior border of prostomium, short longitudinal stripe between posterior eyes, beneath occipital flap, one large transverse stripe dorsally on each chaetiger, and additional longitudinal lines dorso-laterally in some specimens; ventrally, pigmentation as one pair of large, round spots at midline of each chaetiger. Palps irregularly rounded to subpentagonal, basally fused ( Figs 2 A; 3A–B). Prostomium ovate with two pairs of eyes in rectangular to trapezoidal arrangement and, sometimes, one pair of small anterior eyespots; lateral antennae inserted on anterior margin of prostomium, almost twice as long as palps; median antenna inserted on middle of prostomium, between anterior eyes, almost twice as long as lateral antennae ( Figs 2 A; 3A); nuchal organs as one pair of broad semi-circular rows of cilia posterior to eyes of posterior pair, extending dorsally until near base of central antenna and laterally around prostomium, until close to base of palps ( Fig. 3 A, D). Peristomium dorsally shorter than subsequent segments, with rounded occipital flap covering central area of posterior margin of prostomium, partially including posterior pair of eyes ( Figs. 2 A; 3A, D); dorsal peristomial cirri slightly longer than median antenna, ventral peristomial cirri approximately same size as lateral antennae, inserted in ventrolateral position, close to mouth ( Fig. 3 B). Dorsal cirri of chaetiger 1 longer than dorsal peristomial cirri; remaining dorsal cirri alternating longer cirri, as long as dorsal peristomial cirri, and shorter cirri, as long as lateral antennae ( Figs 2 A; 3A). Antennae, peristomial and dorsal cirri with short cirrophores ( Figs 2 A; 3F); cirrostyles with scattered tufts of cilia, arranged in irregular longitudinal rows ( Fig. 3 A–B, D–E). Ventral cirri round to ovate, slightly shorter than parapodial lobes ( Fig. 3 B, E). Parapodial lobes distally bilobed, with rounded lobes, posterior lobe slightly larger ( Fig. 3 B, E). Anterior parapodia with ~15–20 falcigers each, midbody with 10–18, posterior parapodia with 6–10 falcigers each (Table 1); shafts of falcigers subdistally spinulated, with straight tips ( Figs 1 A; 2B–D; 3C, G); connective between shafts and blades spinulated in dorsalmost chaetae, especially on mid- and posterior body chaetigers ( Fig. 2 C–D); blades of falcigers spinulated and bidentate, teeth about same size on anterior chaetigers and in dorsalmost chaetae of mid- and posterior chaetigers ( Figs 2 B–D; 3G), distal tooth larger than subdistal one in ventralmost chaetae of mid- and posterior body chaetigers ( Figs 2 C–D; 3C); blades of falcigers within each parapodium with subdistal tooth progressively more separate from distal tooth ventralwards ( Figs 2 B–D; 3F); blades with inverted dorso-ventral gradation in length, 11–22 µm long on anterior chaetigers, 10–22 µm long on midbody, 9–17 µm long on posterior chaetigers (Table 1). Dorsal simple chaetae only present on posterior chaetigers (Table 1), thin, ~1/3 as thick as shafts of falcigers, slightly sigmoid, subdistally spinulated ( Fig. 2 E); ventral simple chaetae only present on posteriormost chaetigers (Table 1), sigmoid, bidentate, tips resembling those of blades of falcigers, slightly spinulated subdistally, about half as thick as shafts of falcigers ( Fig. 2 F). Anterior parapodia with up to 3 aciculae each, midbody with 1–2, posterior parapodia with 1 acicula each; aciculae subdistally enlarged and slightly spinulated, sometimes with short, acute tip ( Fig. 2 G–H). Pygidium with thin, elongate pair of anal cirri, almost twice as long as posterior dorsal cirri, sometimes wrinkled to pseudoarticulated. Pharynx through 3–4 segments (Table 1), trepan with six teeth and two lateral plates; proventricle through 5–9.5 segments (Table 1), with numerous transverse and oblique muscle cell rows ( Fig. 2 A).

Remarks. Odontosyllis aracaensis sp. nov., belongs to a group of species with relatively short, bidentate falciger blades, which includes O. fulgurans (Audouin & Milne Edwards, 1833) , O. polycera (Schmarda, 1861) , O. dugesiana Claparède, 1864 , O. hyalina Grube, 1878 , O. polyodonta Saint-Joseph, 1887 , O. enopla Verrill, 1900 , O. phosphorea Moore, 1909 , O. octodentata Treadwell, 1917 , O. undecimdonta Imajima & Hartman, 1964 , O. magnanuchalata Hartmann-Schröder, 1965 , O. fulgurans japonica Imajima, 1966 , O. setoensis Imajima, 1966 , O. fulgurans dolerens Westheide, 1974 , O. australiensis Hartmann-Schröder, 1979 , O. luminosa San Martín, 1990 , O. fragilis Kudenov & Harris, 1995 , O. trilineata Imajima, 2003 , O. guillermoi Fukuda & Nogueira, 2006 , O. pentalineata Verdes, Pleijel & Aguado, 2011 , and O. guarauensis sp. nov. A comparison between all these species is provided in Table 2. Except for three of these species, discussed below, O. aracaensis sp. nov., is easily distinguished by the morphology of the pharynx, especially in regards to the trepan, and proventricle, and/or by the pigmentation pattern (see Table 2).

In addition to being sympatric, O. aracaensis sp. nov., shares many features with O. guillermoi , such as the size and shape of the body, trepan, proventricle and aciculae. These species differ, however, on the pigmentation: in O. guillermoi there are two narrow stripes per segment, while in O. aracaensis sp. nov., there is only one broad stripe; the prostomial mask is more complex in O. guillermoi , with stripes along the anterior border and between the eyes, while O. aracaensis sp. nov., has only one stripe along the anterior border of prostomium and below the occipital flap. The falcigers of these species are also similar, but in O. guillermoi the subdistal tooth is distinctly smaller than the distal one and the teeth are more separated from each other, contrary to that seen in O. aracaensis sp. nov.; furthermore, the shafts of falcigers are distally sigmoid in O. guillermoi and distally straight in O. aracaensis sp. nov. ( Fig. 1 A, D).

Odontosyllis aracaensis sp. nov., also resembles O. fulgurans (and O. cf. fulgurans, sensu Fukuda & Nogueira 2006 ) in the morphology of trepan and proventricle, shape of the aciculae, and falcigers with distally straight shafts and bidentate blades. However, O. fulgurans lacks body pigmentation patterns and has falciger blades with teeth of about same size and triangular subdistal tooth ( Fig. 1 B), while in O. aracaensis sp. nov., the teeth are about same size on anterior chaetigers and in the dorsalmost falcigers of mid- and posterior body chaetigers, but the subdistal tooth is distinctly smaller than the distal one in ventralmost falcigers of mid- and posterior body chaetigers ( Figs 1 A; 2B–D).

Odontosyllis fulgurans dolerens Westheide, 1974 also resembles O. aracaensis sp. nov., in all the characters discussed above for O. fulgurans . Furthermore, the falciger blades in this subspecies differ from those in European O. fulgurans in that the subdistal tooth is clearly smaller than the distal one, especially on posterior chaetigers. However, O. fulgurans dolerens can be differentiated from O. aracaensis sp. nov., by possessing a longitudinal grey to black dorsal line, instead of the transverse black stripes on each chaetiger of O. aracaensis sp. nov., and in having nearly all falciger blades with the distal tooth larger than the subdistal one and more falcate than those of O. aracaensis sp. nov. In addition, the new species only has the distal tooth clearly larger than the subdistal one in the ventralmost falcigers of mid- and posterior chaetigers.

Etymology. This species is named after the Araçá (São Sebastião, state of São Paulo), one of the last mangrove spots in that city, a locality constantly threatened by the expansion plans of the neighbouring port of São Sebastião. Most type specimens, including the holotype, were found in the area.

Odontosyllis guillermoi Fukuda & Nogueira, 2006 Figure 1 D

Odontosyllis guillermoi Fukuda & Nogueira, 2006: 225 –229, figs 1–2; Fukuda 2010: 52–56, figs 14–15.

Material examined. Project ‘BIOTA’. Ubatuba—Praia da Fazenda (23°21'25"S 44°51'55"W), on rocky shore: 32 specs (ZUEC-POL 11308), 16 Oct 2001; Praia de Picinguaba (23°22’31”S 44°50’21”W), on rocky shore: 26 specs (MZUSP 995), 9 May 2001; on Sargassum : 46 specs (MZUSP 996), 18 Oct 2001. Caraguatatuba—Praia Martim de Sá (23°37'34"S 45°22'31"W), on Sargassum : 18 specs (MZUSP 993), 16 Mar 2001; on rocky shore: 2 specs (MZUSP 992), 20 Sep 2001. São Sebastião—Praia da Baleia (23°46'S 45°39'W), on rocky shore: 16 specs (MZUSP 983), 8 Apr 2001; 3 specs (MZUSP 984), 13 Dec 2001; on Sargassum : 1 spec. (MZUSP 986), 14 Nov 2001.

Project ‘BioPol-SP’. Ubatuba—Praia do Félix (23°23'S 44°58'W): 3 specs (MZUSP 989), 4 Nov 2002. Caraguatatuba—Praia Martim de Sá (23°37'34"S 45°22'31"W): 2 specs (ZUEC-POL 11312), 22 Jul 2005. São Sebastião—Praia de São Francisco (23°44'54"S 45°24'33"W): 1 spec. (MZUSP 1000), 19 Apr 2003; Praia da Baleia (23°46'S 45°39'W): 1 spec. (MZUSP 988), 2 Nov 2002; Praia do Araçá (23°48'54"S 45°24'24"W): 2 specs (ZUEC- POL 11302), 25 Sep 2003; Praia de Guaecá (23°49'12"S 45°28'07"W): 5 specs (MZUSP 990), 17 Jul 2003; Praia Preta (23°49'16"S 45°24'35"W): 2 specs (MZUSP 999), 18 Jul 2003; Praia de Barequeçaba (23°49'51"S 45°25'52"W): 2 specs (MZUSP 987), 20 Apr 2003; Praia de Toque-Toque Grande (23°50'12"S 45°30'40"W), 21 Jul 2005. São Vicente—Praia das Vacas (23°58'55"S 46°22'48"W): 7 specs. (MZUSP 1003), 16 May 2003; Ilha Porchat (23°59'S 46°22'W): 1 spec. (MZUSP 997), 18 Nov 2002; 5 specs (MZUSP 998), 16 Mar 2003. Guarujá—Praia de Pernambuco (23°58'S 46°'10'W): 3 specs (ZUEC-POL 11314), 4 Oct 2005; Ilha das Palmas (24°00'S 46°19'W): 2 specs (MZUSP 994), 5 Oct 2005. Itanhaém—Praia do Sonho (24°11'S 46°48'W): 1 spec. (MZUSP 1001), 22 Apr 2005. Peruíbe—Praia do Guaraú (24°22'02"S 47°00'35"W): 1 spec. (MZUSP 991), 5 Mar 2007.

Project ‘BioPol-NE’. Mataraca—Barra de Camaratuba (6°36’12’’S 34°57’52’’W): 4 specs (MZUSP 1233), 12 Aug 2010. Baía da Traição—Praia do Farol (6°41’20’’S 34°55’48’’W): 8 specs (MZUSP 1232), 9 Aug 2010; Rio Tinto—Barra de Mamanguape (6°46’9’’S 34°55’2’’W): 34 specs (MZUSP 1234), 11 Aug 2010. Conde—Praia de Jacumã (7°16’40’’S 34°47’54’’W): 1 spec. (MZUSP 1235), 20 Jan 2010; Praia de Tabatinga (7°19’18’’S 34°47’52’’W): 3 specs. (MZUSP 1236), 1 Sep 2011; Praia de Tambaba (7°21’21’’S 34°47’54’’W): 1 spec. (MZUSP 1237), 30 Aug 2011.

Remarks. The specimens agree with the description provided by Fukuda & Nogueira (2006), except for the inverted dorso-ventral gradation in length of the falciger blades, which was misinterpreted in that study.

Figures

FIGURE 1. Dorsalmost (left hand) and ventralmost (right hand) falcigers of posterior chaetigers of the species of Odontosyllis treated in the present paper. (A) O. aracaensis sp. nov.; (B) O. cf. fulgurans; (C) O. guarauensis sp. nov.; (D) O. guillermoi. Scale bar = 10 µm.

FIGURE 2. Odontosyllis aracaensis sp. nov. (Paratype 1, ZUEC-Pol 11891). (A) anterior end, dorsal view; (B) falcigers, anterior chaetiger; (C) falcigers, midbody chaetiger; (D) falcigers, posterior chaetiger; (E) dorsal simple chaeta, posterior chaetiger; (F) ventral simple chaeta, posterior chaetiger; (G) aciculae, anterior chaetiger; (H) acicula, posterior chaetiger. Scale bars: A = 375 µm; B – H = 10 µm.

FIGURE 3. Odontosyllis aracaensis sp. nov., SEM. (A) anterior end, dorsal view; (B) anterior end, ventral view; (C) ventralmost falcigers, mid- to posterior body chaetiger; (D) prostomium and peristomium, dorsal view; (E) midbody parapodia, ventral view; (F) anterior parapodia, dorsal view; (G) intermediate falcigers, mid- to posterior body chaetiger. Scale bars: A = 200 µm; B = 140 µm; C = 2.4 µm; D = 40 µm; E = 32 µm; F = 16 µm; G = 3.2 µm.